1605-1694

French astronomer who established the period of the variable star Mira Ceti (1667). In Astronomia philolaica (1645) he suggests that if a planetary motive force exists it should vary inversely as the square of the distance. Though he rejected this dynamical explanation of planetary motion, preferring instead a purely kinematical account, Boulliau's inverse-square hypothesis was praised by Isaac Newton. A Copernican and supporter of Galileo, Boulliau was one of the first to accept Johannes Kepler's elliptical orbits.